Initial examination (1st and 2nd rows of images):

Clinical presentation: a 49-year-old man was referred for an evaluation of typical complaints of subacute thyroiditis - fever and pain in the region of the left thyroid lasting for 2 weeks. The complaints of the patient had spontaneously resolved a day before the initial examination.

Palpation: the thyroids were hard and not tender.

Functional state: moderate degree of hyperthyroidism with TSH-level 0.001 mIU/L, FT4 31.6 pM/L, FT3 8.29 pM/L. Erythrocyte sedimentation rate was 29 mm/H.

Ultrasonography: there were multiple hypoechogenic areas with blurred borders within echonormal background in both lobes. The vascularization was decreased.

Cytological picture: corresponded to thyroiditis.

Combined clinical-ultrasonographic-cytological diagnosis: subacute, granulomatous de Quervain's thyroiditis.

Suggestion: follow-up examinations.

Follow-up examination 12 months later (third row):

Clinical presentation: the patient had no complaints.

Palpation: no abnormality.

Functional state: euthyroidism with TSH-level 1.09 mIU/L, FT4 16.2 pM/L, anti-TPO 1 U/mL.

Ultrasonography: the thyroid decreased in size as the extent of hypoechogenic areas. There were hypoechogenic lesions with blurred borders already present and the vascularization was already decreased.

Comments.

1. The cytological picture itself was not pathognomic. Theoretically, such a pattern could arise from a Hashimoto's thyroiditis. In this case we found multinucleated giant cells composed of follicular cells and found single epitheloid cells, but the only pathognomic cytological signs of de Quervain's thyroiditis, the multinucleated giant cells composed of epitheloid cells were not present.

2. We perform regular investigations in patients with de Quervain's thyroiditis until the sonographic pattern becomes normal. In more than 40 % of cases, it takes 2 years or more.